The New York Times reports that the crash was likely caused by storms over the Sahara region:

Fierce thunderstorms were pounding the Sahara region where the plane, Flight 5017, would have flown, and the storms probably played a role in bringing the plane down, according to the official, Gen. Gilbert Diendéré, [Burkina Faso's] chief of the general staff.

General Diendéré, head of the crisis committee set up to investigate the flight, told the New York Times that there appeared to be no survivors. According to the AP, the wreckage was found about 31 miles from the border of Burkina Faso. Diendéré spoke to the AP about the search:

"We sent men, with the agreement of the Mali government, to the site, and they found the wreckage of the plane with the help of the inhabitants of the area. ... They found human remains and the wreckage of the plane totally burnt and scattered."

Burkina Faso's government spokesman told the AP that the country will observe 48 hours of mourning.